For many tasks, such as navigation, junction assistance or other driver assistance systems, the position accuracy of GPS (Global Positioning System) and probably also of the future Galileo system is often inadequate in complex traffic situations such as may arise at interchanges or multilane junctions, for example, since it is not possible to identify with sufficient accuracy the lane in which a vehicle is currently situated.
In addition, GPS reception is normally not possible in tunnels or garages, for example. For that reason, position finding resorts to wheel speed sensors, for example, in this case. However, this positioning is worse the more dynamic and the longer the journey without direct GPS reception.